Someone who has been infected with COVID-19 might feel a sense of relief that they’ve developed some immunity and won’t get infected again. But how long do you remain immune, and how immune are you, really?
Since we’ve only been studying COVID-19 for 11 months, experts can’t project too far when examining how long someone remains immune. The good news is there does seem to be immunity that lasts awhile, but that term is very relative and appears to depend on the severity of the infection.
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In a new, non-peer reviewed, pre-print paper from the Imperial College of London, antibody levels were tracked in 365,000 people in England from June 20 through Sept. 28.
Researchers found that in June, 6% of the population had antibodies found through a finger prick test. By September, only 4.4% of the people tested had antibodies.
This is significant because the decrease suggests that over just a few months, the immunity of the population significantly decreased. It also highlights that over 95% of the population tested had no antibodies, which isn’t promising for any level of herd immunity.
Another new study from the journal Nature Microbiology looked at the antibody response of 65 people with COVID-19.
Researchers found that over 95% of the patients developed an antibody response after eight days from symptom onset, but the amount of neutralizing antibody produced was highest in patients with the most severe symptoms.
People who produced the highest levels of antibodies continued to produce them for more than two months after their initial infection. But for those who initially produced fewer antibodies, they became undetectable within a month and a half.
There’s general agreement that the antibody response to COVID-19 is not permanent, but exactly how long it might be protective isn’t completely clear. In fact, a study just released Wednesday afternoon in the journal Science showed stable antibody levels for five months. The difference might have been in the specific antibody researchers studied.
Different vaccines might produce different responses, depending on what they generate antibodies to and how they do it, because there are different techniques being tested. Some might have better long-term effectiveness, but others might require boosters.